The car the boys buy is autographed by Rick Mears but in the overhead shot of the car while it's on the fireplace mantle there is no visible Autograph.
When the Taylor boys are looking through the baseball card catalog, Brad suggests that if they spend $150 on a card now, someday it could be worth $6 billion. Jill replies that she doesn't think every card gives a 40 million percent return. Her math is off by a few zeros. It would be 4 billion percent of their $150 to equal 6 billion.